During the past three decades, the key-block method has been developed and successfully used to analyze the stability of jointed rock masses for both rock slopes and underground engineering. Implementation of the key-block method has been manifested as two main forms: the vector technique (Warburton, 1981) and the stereographical technique (Goodman & Shi, 1985). Zhang & Kulatilake (2003) put forward a new stereoanalytical method, in which analysis takes place of the stereographic projection.